App: 25cms long Interesting facts: - Weight: 50 - 150 g - Size: 4 - 16 cm - Life expectancy: 5 - 6 years - Distribution: Europe, South America, Australia - Colours: black, gray It is probably because of the time of day. Bats sleep during the day and become active only after sunset. They hunt insects at night. They can hunt prey at up to 50 km/h. Bats can see at night by using ultrasonic waves. This means they emit sounds that are so high that we humans cannot hear. The ultrasound waves bounce off obstacles and come back again. Due to the nature of the waves and the time it takes for them to come back to the bats, they know where and how far away the obstacle is located.